The cell transfusion service will continue to provide platelets and granulocytes for transfusion. An expanded program to provide HL-A matched platelets is planned as well as parallel laboratory studies to predict donor-recipient compatability in vitro. The effects of various storage methods on platelet function are being investigated. Extensions of previous studies dealing with platelet freezing, the effects of cryoprotective agents on cell function are in progress. Efforts are being made to improve the in vivo function of granulocytes obtained by filtration leukophoresis and to increase the efficiency of cell procurement with the Model 30 Blood Processor.